Nuruk

Wheat, rice (of both the glutinous and non-glutinous types), and barley are used to make nuruk, either as whole grain or in the form of grits or flour.

The dry grain is moistened, shaped into a large cake, and hung up to ferment for 2‒4 weeks in an ondol room.

[8] Traditionally, nuruk was prepared on a small scale by families in summer or autumn, especially in July when the ambient temperature is between 20–30 °C (68–86 °F) on the Korean peninsula.

Rhizopus provides the enzyme protease and lipase, which break down the protein and fat in the outer layers of the rice grain (endosperm), allowing the amylase access to the starches in the inner part.

Nuruk made in the southern coastal areas surrounding Busan, for example, have a higher lactic acid bacteria content due to the warmer climate and humidity.